The present invention relates to heaters in general and, more particularly, to an air heater with safety controls.
Various types of fixed, mobile and portable heaters are known in the art. For example see U.S. Pat. Nos. 2,966,347; 2,972,208; 3,050,111; 3,160,401; 3,211,439; 3,418,452; 3,624,350; 4,053,732; and French Patent No. 916.111.
Use of the prior art heaters presents problems from a safety standpoint. For example, if air flow through the heater is reduced or terminated, dangerous overheating can occur. Similarly, even if air flow continues through the heater the heater itself may become too hot.
It is accordingly a general object of the present invention to provide an air heater with safety controls.
It is a specific object of the invention to provide an air heater that senses a differential pressure between static air pressure and the air velocity pressure within the heater housing.
It is an other object of invention to provide an air heater which senses the temperature of a portion of the heater housing.
It is a still further object of the present invention to provide for shut down of the heat source within the heater housing in the event that the differential pressure between static air pressure outside the heater housing and the air velocity pressure within the housing drops below a predetermined minimum pressure differential.
It is a still further object of the invention to provide for shut down of the heat source in the event that the temperature of a portion of the housing exceeds a preset temperature.
It is a feature of the invention that the safety controls can be implemented utilizing conventional components including electro-mechanical components.
It is another feature of the invention that the safety controls can be implemented so that a manual "restart" is required in the event that the heat source is shut down in response to the above mentioned pressure and/or temperature failure conditions.